JP3657476B2 - Rolling bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rolling bearing filled with a lubricant-containing polymer.
[0002]
[Prior art and problems to be solved by the invention]
For example, in a papermaking machine, the papermaking process is sequentially moved while pulling both corners of the leading end of the paper-like paper that has been made with a pair of ropes. The paper itself passes between the rollers, and each rope is wound around a number of carrier wheels sequentially. Each carrier wheel is rotatably supported by a rolling bearing.
[0003]
This carrier wheel rolling bearing is exposed to particularly harsh environments in the dryer part that dries the paper during the paper making process. This is because, for example, the dryer part has a temperature of 100 to 120 ° C., a high temperature and high humidity of 100%, and water may be directly applied to the rolling bearing.
Although the above-mentioned rolling bearing is equipped with a general sealing member, it is difficult to completely seal the rolling bearing even if it has the above-mentioned sealing member because of its structure. Therefore, moisture may enter the rolling bearing and generate rust.
[0004]
Therefore, it is conceivable to use the rolling bearing with grease filled. In this case, since the penetration of moisture into the bearing can be suppressed by the filled grease, the effect of rust prevention can be expected. However, due to the filled grease, the torque during rotation of the bearing increases. Further, as described above, since complete sealing is difficult, a part of the filled grease may leak to the outside due to temperature expansion or the like.
On the other hand, rolling bearings of the type that contain lubricating oil in the resin and lubricate with the lubricating oil that oozes out are provided, but when this type of rolling bearing is used for the above-mentioned applications, rust is affected by the intruding moisture. There is a problem that the life is shortened rather than the above-mentioned grease-filled type rolling bearing.
[0005]
The same problem is caused by bearings for conveyors of continuous car washers that carry vehicles continuously on a conveyor, bearings for pickling line rolls for steel rolling mills, and bearings for wheels of agricultural machines such as cultivators. It also exists in bearings for wheels of a transport vehicle that is automatically operated indoors and outdoors in a factory.
The present invention has been made in view of the above problems, and it is an object of the present invention to provide a rolling bearing that is unlikely to rust even in a harsh environment, and that has a low torque and does not cause the lubricant to leak.
[0006]
[Means for Solving the Problems and Effects of the Invention]
As a problem-solving means for achieving the above object, the invention according to claim 1 provides a space obtained by sealing a space between an inner ring and an outer ring with a plurality of rolling elements between each other by a pair of sealing members. In the rolling bearing formed in a ring and filled with a lubricant composition containing a resin polymer, the lubricant composition is disposed in a region covering at least the rolling elements in the space, and the lubricant composition in the space Grease is filled in a region between the corresponding sealing members, and the sealing member includes an annular rubber body, and the rubber body elastically contacts a side surface of the lubricant composition. In addition to having an inward lip, only the lip makes sliding contact with the side surface of the lubricant composition .
[0007]
In the present invention, since lubrication is performed with the lubricant that oozes out from the lubricant composition, low torque can be achieved and no lubrication is required. Moreover, since the outer side of the lubricant composition that covers the rolling elements is further covered with grease, it is possible to suppress the intrusion of moisture into the space, thereby preventing the occurrence of rust and extending the life of the bearing. . In addition, since the amount of grease filled in the remaining area excluding the lubricant composition in the space is small, there is no possibility that the lubricating oil will leak out as in the type in which the entire space is filled with grease. In particular, since the sealing member has a lip that elastically contacts the side surface of the lubricant composition, the grease filled in the remaining area excluding the lubricant composition in the space is surely prevented from leaking to the outside. can do.
According to a second aspect of the present invention, in the first aspect, the grease filled in the region between the lubricant composition in the space and the corresponding sealing member is more than the annular lip of the rubber main body. It is arranged radially outward.
According to a third aspect of the present invention, in the first or second aspect, the inner ring includes annular grooves at both ends of the outer periphery, and the sealing member has a portion that enters the annular groove to form a labyrinth structure. It is a feature.
[0008]
A fourth aspect of the present invention is characterized in that, in the first , second or third aspect , the volume ratio of the lubricant composition in the space is 60 to 80%. In the present invention, sufficient lubricity can be ensured, and interference between the lubricant composition and the sealing member can be prevented. On the other hand, when the volume ratio is less than 60%, the lubricant composition is insufficient in the amount of the lubricant, and sufficient lubricity cannot be expected. When the volume ratio exceeds 80%, the lubricant composition interferes with the sealing member. As a result, the operation of the rolling bearing may become unstable.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a sectional view of a rolling bearing according to an embodiment of the present invention. With reference to FIG. 1, the rolling bearing 1 is composed of, for example, a ball bearing, and a plurality of rolling elements 5 composed of, for example, balls held by a cage 4 between the outer ring 2 and the inner ring 3.
Further, the corresponding end portions of the outer ring 2 and the inner ring 3 are each sealed with a sealing member 6, and a space 7 formed inside is filled with an annular lubricant composition 8 and grease 9.
[0011]
The lubricant composition 8 is shaped to occupy a region that just covers the rolling elements 5 and the cage 4, and the remaining region is filled with grease 9. The volume ratio of the lubricant composition 8 in the space 7 is set to 60 to 80%. On the other hand, the grease 9 is filled in a region between each sealing member 6 and the end face of the lubricant composition 8 facing the sealing member 6, and the volume ratio of the grease 9 in the space 7 is 20 to 40%.
[0012]
An annular recess 10 is formed at each end of the inner periphery of the outer ring 2, and an annular groove 11 is formed at each end of the outer periphery of the inner ring 3. Each sealing member 6 includes an annular rubber body 12 and an annular reinforcing plate 13 that reinforces the body 12. The main body 12 includes: (1) an annular outer peripheral seal portion 14 accommodated and held in the annular recess 10 of the outer ring 2; (2) a first portion 17 that enters the annular groove 11 of the inner ring 3 and forms a labyrinth structure; the inner peripheral seal 15 having a lip 18 of the surface of the lubricant composition 8 as a second portion resiliently pressing, (3) main body portion 16 for continuous outer peripheral seal portion 14 and the inner peripheral seal 15 together And. The reinforcing plate 13 is made of an annular metal plate having an L-shaped cross section that reinforces the sealing member 6 along the main body portion 16 and the outer peripheral seal portion 12.
[0013]
The lubricant composition 8 includes: (a) a polymer using a thermoplastic resin such as ultra high molecular weight polyethylene resin, polypropylene or polymethylpentene; or a thermosetting resin such as polyether polyurethane resin; (b) metal soap. A grease selected from type grease and non-metallic soap type organic grease, or a lubricating oil such as poly-α-olefin, and (c) a rust preventive additive is used.
In particular, the polymer (a) is a polyurethane obtained by using an amine curing agent in a urethane prepolymer having an isocyanate group content of about 6 to 10% by weight and a molecular weight of about 400 to 10,000. Resins are preferably used. Moreover, the hardness of the lubricant composition 8 after curing is preferably 60 to 85 in terms of an international rubber hardness unit (measurement method described in IRHD, JIS K6253).
[0014]
In the above urethane prepolymer, the lubricant composition using a polymer having an isocyanate group content of less than 6% by weight does not reach a hardness after curing of 60 IRHD, and the torque increases during operation even when filled in a bearing. Since the lubricant composition is easily damaged, the purpose of extending the life cannot be achieved. On the other hand, if the isocyanate group content exceeds 10% by weight, the supply of oil from the lubricant composition is reduced and the life is shortened, which is not suitable as a bearing lubricant.
[0015]
Examples of the urethane prepolymer include commercially available products such as Hyprene HL-951, Hyprene HL-6502, Hyprene L-315, Hyprene AX-596C, Hyprene P-760 (all of which are manufactured by Mitsui Chemicals).
As the ultra high molecular weight polyethylene, those having an average molecular weight of about 1 million to 6 million, particularly 2 million or more and a melting point of about 100 to 140 ° C. are preferably used.
[0016]
Examples of greases that are component (b) of the lubricant composition include greases containing an alkali metal salt, alkaline earth metal salt or aluminum salt of an aliphatic monocarboxylic acid having 12 to 24 carbon atoms as a thickener: Grease containing an alkali metal salt or alkaline earth metal salt of an aliphatic monocarboxylic acid having 12 to 24 carbon atoms containing at least one hydroxyl group as a thickener: at least one type having 12 to 24 carbon atoms Calcium containing an aliphatic monocarboxylic acid, an aliphatic monocarboxylic acid having 12 to 24 carbon atoms containing at least one hydroxyl group, and a calcium salt of an aliphatic monocarboxylic acid having 2 to 11 carbon atoms as a thickener Complex soap grease; aliphatic monocarboxylic acid having 12 to 24 carbon atoms and aromatic monocarboxylic acid having 7 to 24 carbon atoms Aluminum complex soap grease containing an aluminum salt of boric acid as a thickener; at least one aliphatic monocarboxylic acid having 12 to 24 carbon atoms, aliphatic having 12 to 24 carbon atoms containing at least one hydroxyl A monocarboxylic acid and at least one aliphatic dicarboxylic acid or dicarboxylic acid diester having 2 to 12 carbon atoms, or aromatic monocarboxylic acid or monocarboxylic acid ester or phosphate ester having 7 to 24 carbon atoms, or Lithium complex soap grease using lithium salt of borate ester as thickener; diurea compound (in the formula represented by R ¹ NHCONHR ² NHCONHR ¹ , R ¹ is linear or branched having 6 to 24 carbon atoms) alkyl group a saturated or unsaturated, R ² is the number of carbon atoms Include greases containing represents.) A divalent aromatic hydrocarbon group having 15.
[0017]
Base oils in these greases are those used in ordinary lubricating greases. For example, synthetic hydrocarbon oils having a kinematic viscosity at 40 ° C. of 50 to 460 mm ² / s (eg, poly α-olefin oil) are preferably used. Is done.
Examples of the lubricating oil include polyalphaolefin oil, mineral oil, diester oil, polyol ester oil, alkyl diphenyl ether oil, silicone oil, paraffin oil, fluorine oil, and the like.
[0018]
As said amine type hardening | curing agent, that whose content of the amino group is 1 to 10 weight% is suitable. Examples of such amine curing agents include MC-506, MC-591, MDA-220 (all of which are manufactured by Mitsui Chemicals), Adeka Hardener CA125 (Asahi Denka Kogyo), Etacure 100 (manufactured by Albemarle Asano), and the like. Aromatic polyamine-based curing agents, wandamine HM (4,4'-diaminodicyclohexylmethane) (New Nippon Rika), 1,2-diaminocyclohexane (DuPont) and other cycloaliphatic amine curing agents, hexamethylenediamine (DuPont) And aliphatic amine curing agents such as ethylenediamine (Kanto Denka Kogyo), Trilon BS (ethylenediaminetetraacetic acid) (BASF), and Jeffamine D-2000 (polyoxyalkylenediamine) (Mitsui Texaco Chemical).
[0019]
Usually 18.3 to 79.6% by weight of urethane prepolymer of component (a); 20 to 80% by weight of grease of component (b); and 0.1 to 6.7% by weight of amine curing agent, Prepared to contain.
Examples of the anticorrosive additive (c) include metal sulfonates such as sodium, potassium, calcium and barium, synthetic sulfonates such as dinonylnaphthalene sulfonate and octadecylbenzene sulfonate, sorbitan monooleate, and the like. Can be exemplified.
[0020]
In particular, those containing a first additive containing a metal sulfonate and a second additive containing sorbitan are preferred. The first additive may contain the above synthetic sulfonate. Moreover, it is preferable to mix | blend a 1st additive and a 2nd additive with a substantially equal content rate, when improving a rust prevention effect.
As a content rate of the rust preventive additive with respect to the whole quantity of the lubricant composition 8, it is preferable that it is 2 to 6 weight%. This is because if the content of the rust preventive additive is less than 2% by weight, a sufficient rust preventive effect cannot be obtained, and if it exceeds 6% by weight, the lubrication life is reduced.
[0021]
The lubricant composition 8, other rust additives, if necessary, antioxidants, and additives such as extreme pressure additives for improving wear resistance may be added.
Examples of the antioxidant include phenolic antioxidants. Examples of extreme pressure additives include compounds such as chlorinated paraffin, tricresyl phosphate, and zinc dialkyldithiophosphate.
The grease 9, but are not particularly limited, the compatibility with the lubricant composition described above (b) those of the components of the grease and the same type are preferable.
[0022]
In the lubricant composition containing the components (a), (b) and (c), the total amount of the components (a) and (c) is preferably 20 to 80% by weight based on the total amount of the composition, Preferably it is 40 to 60% by weight. When the amount is less than 20% by weight, the lubricant composition is too soft to become a solid lubricant. On the other hand, when the amount exceeds 80% by weight, the lubricant composition is too hard and close to a resin, and the lubricant does not ooze out easily, resulting in poor lubrication.
[0023]
The weight ratio of the urethane prepolymer to the amine curing agent is preferably 200: 1 to 11: 1, more preferably 50: 1 to 20: 1. When the ratio of the urethane prepolymer is lower than 200: 1, the curing rate (time until solidification) becomes slow, which is not practical, and when the ratio of the amine-based curing agent exceeds 11: 1, it is not economical.
The above-mentioned lubricant composition can be obtained by mixing and blending the above-mentioned formulation in the above-described quantitative ratio. These processes are performed after the urethane prepolymer and the amine-based curing agent are mixed with grease using a static mixer or a reaction injection molding device so that the urethane prepolymer is hardened in the roller bearing. It is preferable to carry out such that mixing is also performed while filling. When filling with a static mixer or the like, the amine-based curing agent is blended with the grease (b) and usually blended so that the lubricant composition is in a mixed state of a predetermined blending ratio in the rolling bearing. Is preferred. Other additives may be added to (a), (b), or both so as to have a predetermined amount.
[0024]
The lubricant composition filled in the rolling bearing as described above is cured by leaving it at room temperature to 170 ° C. for about several minutes to 24 hours.
According to the present embodiment, since lubrication is performed with the lubricant that oozes out from the lubricant composition 8 that covers the rolling elements 5, low torque can be achieved, and no lubrication is required and maintenance-free is realized. be able to.
Moreover, since the outer side of the lubricant composition 8 covering the rolling elements 5 is further covered with the grease 9, it is possible to suppress the intrusion of moisture into the space 7 sealed by the sealing member 6. As a result, the occurrence of rust can be prevented and the life of the bearing can be extended.
[0025]
Further, the volume ratio of the grease 9 filled in the space 7 in the space 7 is as small as 20 to 40%, for example, and lubrication is effected by the influence of temperature expansion or the like as in the type in which the entire space is filled with grease. There is no risk of oil leaking. In particular, since the sealing member 6 are a lip 18 provided for the lubricant composition 8, the high sealing properties against grease 9.
Hereinafter, another embodiment of the present invention will be described. This embodiment is the same as the above embodiment except that ultra high molecular weight polyethylene is used as the polymer of the component (a) and poly α-olefin is used as the lubricating oil of the component (b). The ultra high molecular weight polyethylene is appropriately blended so that the ratio to the total amount is in the range of 10 to 50% by weight. It mix | blends so that the ratio for which poly-alpha olefin accounts to the total amount may exist in the range of 44 to 88 weight%. The blending ratio of the anticorrosive additive as the component (c) is similarly selected within the range of 2 to 6% by weight. Another rust additives in the lubricant compositions, if necessary, antioxidant described above, and an additive such as extreme pressure additives for improving wear resistance may be added.
[0026]
In addition, it can replace with or use together with the antirust additive illustrated as a component (c) in said each embodiment, and can use a vaporizable antirust agent. Vaporizable rust preventives include dicyclohexylammonium nitrite (DICHAN), cyclohexylamine carbamate (CHC), diisopropylammonium nitrite (DIPAN), nitronaphthalene ammonium nitrite (NITAN), MBT, benzotriazole, methylbenzotriazole, dicyclohexyl Examples include ammonium caprylate and cyclohexylammonium laurate. The blending ratio lubricant composition of volatile corrosion inhibitor, preferably 2 to 10 wt%.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a rolling bearing according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rolling bearing 2 Outer ring 3 Inner ring 4 Cage 5 Rolling body 6 Sealing member 7 Space 8 Lubricant composition 9 Grease

Claims (4)

The space obtained by sealing a pair of sealing members between the inner ring and the outer ring interposed a plurality of rolling elements between each other, formed by filling the lubricant composition comprising a and resin polymer an annular rolling bearing In
The lubricant composition is disposed in a region covering at least the rolling elements in the space,
The area between the lubricant composition and the corresponding sealing member in the space is filled with grease ,
The sealing member includes an annular rubber body,
A rolling bearing characterized in that the rubber body has an axially inward lip that elastically contacts the side surface of the lubricant composition, and is in sliding contact with the side surface of the lubricant composition only by the lip. . The grease filled in the region between the lubricant composition in the space and the corresponding sealing member is disposed radially outward from the lip of the rubber main body having the annular shape. The rolling bearing according to claim 1. The rolling bearing according to claim 1 or 2, wherein the inner ring includes annular grooves at both ends of the outer periphery, and the sealing member has a portion that enters the annular groove to form a labyrinth structure . 4. The rolling bearing according to claim 1, wherein the volume ratio occupied by the lubricant composition in the space is 60 to 80%.

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